1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Sindrei [870]
3 years ago
10

On your first day at work as an electrical technician, you are asked to determine the resistance per meter of a long piece of wi

re. The company you work for is poorly equipped. You find a battery, a voltmeter, and an ammeter, but no meter for directly measuring resistance (an ohmmeter). You put the leads from the voltmeter across the terminals of the battery, and the meter reads 13.0 V. You cut off a 20.0 m length of wire and connect it to the battery, with an ammeter in series with it to measure the current in the wire. The ammeter reads 7.60 A. You then cut off a 40.0 m length of wire and connect it to the battery, again with the ammeter in series to measure the current. The ammeter reads 4.50 A. Even though the equipment you have available to you is limited, your boss assures you of its high quality: The ammeter has very small resistance, and the voltmeter has very large resistance. What is the resistance of 1 meter of wire?
Physics
1 answer:
Lostsunrise [7]3 years ago
3 0

Answer:

0.06\Omega/m

Explanation:

Firstly, when you measure the voltage across the battery, you get the emf,

E = 13.0 V

In order to proceed we have to assume that the voltmeter offers no loading effect, which is a valid assumption since it has a very high resistance.

Secondly, the wires must be uniform. So the resistance per unit length is constant (say z). Now, even though the ammeter has very little resistance it cannot be ignored as it must be of comparable value/magnitude when compared to the wires. This is can seen in the two cases when currents were measured. Following Ohm's law and the resistance of a length of wire being proportional to it's length, we should have gotten half the current when measuring with the 40 m wire with respect to the 20 m wire (I=\frac{V}{R}). But this is not the case.

Let the resistance of the ammeter be r

Hence, using Ohm's law we get the following 2 equations:

\frac{13}{20z+r} =7.6   .......(1)

\frac{13}{40z+r} =4.5     ......(2)

Substituting the value of r from (2) in (1), we have,

13=152z+7.6\times\frac{13-180z}{4.5}

which simplifying gives us, z=0.0589\Omega/m\approx0.06\Omega/m (which is our required solution)

putting the value of z in either (1) or (2) gives us, r = 0.5325 \Omega

You might be interested in
According to Kepler's Third Law, a solar-system planet that has an orbital radius of 4 AU would have an orbital period of about
NARA [144]

Answer:

Orbital period, T = 1.00074 years

Explanation:

It is given that,

Orbital radius of a solar system planet, r=4\ AU=1.496\times 10^{11}\ m

The orbital period of the planet can be calculated using third law of Kepler's. It is as follows :

T^2=\dfrac{4\pi^2}{GM}r^3

M is the mass of the sun

T^2=\dfrac{4\pi^2}{6.67\times 10^{-11}\times 1.989\times 10^{30}}\times (1.496\times 10^{11})^3    

T^2=\sqrt{9.96\times 10^{14}}\ s

T = 31559467.6761 s

T = 1.00074 years

So, a solar-system planet that has an orbital radius of 4 AU would have an orbital period of about 1.00074 years.

6 0
3 years ago
The different shapes of the moon seen from Earth are called
Anastaziya [24]

Answer:

phases of moon

Explanation:

.................

3 0
3 years ago
Read 2 more answers
A spelunker is surveying a cave. She follows a passage that takes her a distance 184 m straight west, then a distance 220 m in a
Sever21 [200]
Refer to the diagram shown below.

Define the unit vector i to point in the eastern direction, and the unit vector j to point in the northern direction.

The first distance is 184 m west. It is represented by
d₁ = -184 i

The second distance is 220 m at 30° south of east. It is
d₂ = 220(cos 30° i - sin 30° j) = 190.53 i - 110 j

The third distance is 104 m at 80 east of north. It is
d₃ = 104(sin 80° i + cos 80° j) =  102.42 i + 18.06 j

Let the fourth distance be 
d₄ = a i + b j

Because the traveler ends back at the original position, the vector sum of the distances is zero. It means that each component of the vector sum is zero.

The x-component yields
-184 + 190.53 + 102.42 + a = 0
a = -108.95

The y-component yields
0 - 110 + 18.06 + b = 0
b = 91.94

The magnitude of the fourth displacement is
√[(-108.95)² + 91.94² ] = 142.56 m

The direction is at an angle θ north of west, given by
θ = tan⁻¹ (91.94/108.95) = 40.2°

Answer:
The fourth displacement has a magnitude of 142.56 m. It is about 40° north of west.

7 0
3 years ago
Read 2 more answers
This dude was sitting in the chair. Someone pulls the chair out from under him. He does not move in the direction of the chair.
Oksanka [162]

Answer:

This shows inertia because inertia is an object's resistance to change in motion. When the person (imma call them a she) who pulled the chair from under the guy did that, the chair was the one affected by the force of the girl, not the guy. The guy continued heading in the direction he was originally going, which was down.

At least, that's about how I would answer this question.

8 0
2 years ago
What are some common characteristics that infectious agents like viruses bacteria fungi and parasites have in common and what ar
CaHeK987 [17]

Answer: Some can and can not kill you

Explanation:

6 0
3 years ago
Other questions:
  • Earthquakes with a very deep focus are usually located along ________.
    13·2 answers
  • How many chirps will a snowy tree cricket give is 21 seconds at a temperature of 22 degree celcius
    6·1 answer
  • 。and 。 are needed to describe a force
    15·1 answer
  • A 215-kg load is hung on a wire of length of 3.60 m, cross-sectional area 2.00 10-5 m2, and Young's modulus 8.00 1010 N/m2. What
    6·1 answer
  • A cheetah can go from a state of resting to running at 20 m/s in just 2 seconds.
    5·1 answer
  • I need help on #9 (it's side ways sorry...)
    14·2 answers
  • A square piece of tin has 12 inches on a side. An open box is formed by cutting out equal square pieces at the corners and bendi
    14·1 answer
  • A 300 gg bird flying along at 5.7 m/sm/s sees a 10 gg insect heading straight toward it with a speed of 29 m/sm/s (as measured b
    14·1 answer
  • Why do some organisms never turn into fossils?
    9·1 answer
  • Which plate is made up almost entirely of oceanic crust
    14·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!